1. Field of the Invention
The invention relates to apparatus and methods for sorting objects such as fruits, by categories, such as size, shape, weight and color.
2. Related Art
Object sorting apparatus, in particular fruit sorters, typically have an intake area which receives quantities of fruit. In order to sort the fruit by quality or grade, for example, by size, color, or other characteristics, it is necessary to singulate the fruit so that individual pieces can be inspected. Upon inspection, each piece of fruit can be graded according to size, weight, color, or other desired parameter, and then transferred to a conveyor so that the fruit can be deposited in appropriate collecting bins. One such system is disclosed in U.S. Pat. No. 5,197,585 to Blood. Blood discloses an object sorter having a singulation system with a first object conveyor having independently rotating wheels pivotally attached to and transporting a proximate portion of the object holder through the singulation section of the apparatus. The object holder has a distal end positioned between a first pair of wheels and a cup shaped portion between the distal and proximate ends. The wheels are located a lateral distance across from each other so that objects placed in the singulation section contact the wheels without dropping into the object holder. A first independently adjustable speed belt contacts the first object conveyor wheels to rotate the wheels at a substantially constant speed in the singulation section. This causes singulation of the objects contacting the wheels.
Blood also illustrates a preferred configuration which employs separate belts for each row of wheels. By using separate belts for each row of wheels, it is possible to run the belts at either the same speed to achieve rotation or at different speeds to rotate the objects, such as fruit, about different axes simultaneously.
Blood also discloses a sorting section having wheels receiving objects from the singulation section. The sorting section determines a measurement parameter for each object received and sorts the objects according to the measurement parameter. A second independently adjustable speed belt contacts the wheels in the sorting section to drive them at a rate to cause a complete, progressive rotation of each fruit item contacting the wheels as it passes through the sorting section. Blood notes that it is possible to employ separate belts for each row of wheels to obtain rotation of the fruit about more than one axis in the sorter section also.
The object holder disclosed by Blood in U.S. Pat. No. 5,197,585 facilitates color sorting, but is not adapted to measuring weight. Objects to be weighed are transferred to a separate carrier. Thus, there is a need for a single carrier that can be used for sorting by weight and color. Moreover, modern systems demand faster operation.